TWI411074B - Fine-pitch matrix connectors - Google Patents

Abstract

Fine-pitch matrix connectors that are fabricated through micromechanical technology have self-detecting mechanism for co-planarity and normal force. The matrix connectors can provide low and stable contact resistance under small normal force, which improves the transmission quality of electrical signals.

Description

Fine pitch array type connector

This invention relates to an array connector and, more particularly, to a fine pitch array connector.

Generally, the array connector is limited by the mold and the process, and the minimum terminal spacing can only reach 0.8mm. Moreover, due to the plastic body of the array connector, the phenomenon of warpage is easily generated when the plastic is shot, with the array connector foot. As the bit increases, it will be difficult to control the coplanarity between the feet. In addition, as the BGA chip increases the external IO connection pin and the pitch becomes smaller, it is more difficult to measure the coplanarity of the wafer solder ball by conventional optical measurement.

In addition, with the development of the fine pitch of the connector, the positive force that the single terminal can provide will also be reduced, resulting in excessive contact resistance, which greatly affects the transmission quality of the signal.

In practical applications, if the body structure of the array connector can be improved, the miniaturized array connector can maintain a low and stable contact resistance under a low positive force, which can enhance the array type. Connector electrical connection characteristics. In addition, if the array connector is used to simultaneously measure the coplanarity of the wafer solder balls, the industrial utilization value can be greatly increased.

The invention provides a fine pitch array type connector with self-coplanarity and positive force detection mechanism. The array type connector utilizes the good mechanical and electrical properties of the carbon nanotubes to provide a small and stable contact resistance under low positive force.

The invention provides a fine pitch array type connector with self-coplanarity. Since the connector body is manufactured by a silicon wafer, it can provide a strong tough structural rigidity of the body without causing the behavior of the body warping, affecting Reliability when using the connector.

The invention provides a fine pitch array type connector array type, which is capable of fabricating a low and stable contact resistance array type connector having a carbon nanotube structure through a microelectromechanical process.

The present invention provides a connector structure including an annular body structure and a columnar structure located at the center of the annular body structure, a plurality of first block structures on the annular body structure, and a second structure on the columnar structure. a block structure, at least one cantilever structure, a plurality of solder bumps on the first block structures, and a carbon nanotube layer on the second block structure. Wherein the cantilever structure is connected to the second block structure and the at least one first block structure, and the cantilever structure and the first block structure further comprise a piezoelectric material layer or a piezoresistive material layer. Through the piezoelectric material layer or the piezoresistive material layer, the displacement of the cantilever structure can be sensed, and the coplanarity of the wafer solder ball can be measured.

In accordance with a preferred embodiment of the present invention, in the connector structure described above, the annular body structure and the columnar structure are laminated structures including a ruthenium oxide layer on a surface of the semiconductor substrate.

According to a preferred embodiment of the present invention, in the connector structure, the first and second block structures and the cantilever structure are a laminated structure including a polysilicon layer and a seed on the polysilicon layer. A layer and a metal layer on the seed layer.

In accordance with a preferred embodiment of the present invention, a layer of piezoelectric material in the connector structure is located between the polysilicon layer and the seed layer.

In accordance with a preferred embodiment of the present invention, the layer of piezoresistive material in the connector structure is a doped region located in the polysilicon layer.

According to a preferred embodiment of the present invention, in the connector structure, the material of the piezoelectric material layer comprises zinc oxide.

According to a preferred embodiment of the present invention, in the connector structure, the material of the piezoresistive material layer comprises boron or germanium.

According to a preferred embodiment of the present invention, in the connector structure, the material of the metal layer comprises aluminum, copper or gold.

According to a preferred embodiment of the present invention, in the connector structure, the material of the seed layer comprises titanium, gold or chromium.

According to a preferred embodiment of the present invention, in the connector structure, the material of the solder bump comprises tin, tin-silver alloy or tin-lead alloy.

Since the connector structure proposed by the present invention is designed to measure the coplanarity or positive force of the wafer solder ball by using a piezoelectric or piezoresistive sensing mechanism, the range of application of the product can be improved.

The contact surface of the micro connector structure provided by the invention further has a carbon nanotube layer, which can reduce the contact resistance. The micro connector structure provided by the present invention is particularly suitable for use in a fine pitch (less than 500 micron) microcontact electrical connection structure.

In addition, the method of fabricating the connector structure of the present invention can be easily integrated into current MEMS processes, thereby not adding additional cost.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

1A-1B and FIGS. 1F-1H are cross-sectional views showing a manufacturing process of an array connector according to an embodiment of the present invention, and FIGS. 1C-1E illustrate a manufacturing process of an array connector according to an embodiment of the present invention. Top view.

Referring to FIG. 1A, a substrate 100 is first provided. The substrate 100 is, for example, a semiconductor germanium wafer or wafer. First, the germanium oxide layer 102 is grown on the upper surface 100a of the substrate 100 by, for example, thermal oxidation. A polysilicon layer 104 is then deposited over the yttrium oxide layer 102 using, for example, low pressure chemical vapor deposition (LPCVD). A patterned thin film piezoelectric material layer 106 is then formed on the polysilicon layer 104. The material of the piezoelectric material layer 106 is, for example, zinc oxide (ZnO).

Referring to FIG. 1B, a sub-layer 108a and 108b are respectively deposited on the upper surface 100a and the lower surface 100b of the substrate 100 by, for example, electron gun vacuum evaporation. The seed layer material is, for example, chromium/gold (Cr/Au) or titanium/gold (Ti/Au). Next, a subsequent electroplating process is performed on the seed layer 108a/108b, and a metal layer 110a/110b is formed on the front and back sides of the substrate 100, respectively. The metal layer 110a/110b material is, for example, aluminum, copper or gold.

Referring to FIG. 1C, a metal layer 110a (FIG. 1B) on the front side of the substrate 100 is patterned by a lithography etching step to form a contact pad 110c and a wire 110d.

Referring to FIG. 1D, a pattern of solder is defined by a lithography etching step, followed by an electroplating process to form solder bumps 120. Before forming the solder bumps 120, it may be further included to form another layer 112 (FIG. 1F) and then plated to form the solder bumps 120. The solder bumps 120 can provide a spacer height for use as a spacer. The material of the solder bumps includes tin, tin-silver alloy or tin-lead alloy. However, if a subsequent formation of the solder bump does not require a seed layer, this step can also be omitted.

Referring to FIG. 1E, the polysilicon layer 104 (FIG. 1B) on the front side of the substrate 100 is patterned by a lithography etching step, and the pattern of the patterned polysilicon layer 104a (FIG. 1F) is the same as the patterned metal layer 110a on the front side of the substrate 100. As shown here, the piezoelectric sensing mechanism formed by the piezoelectric material layer 106 and the metal layer is utilized, and in the subsequent connection process, the purpose of the coplanarity detection or the positive force detection can be achieved.

In FIG. 1E, the pattern of the patterned polysilicon layer 104a includes at least four cantilevers (subsequently as a suspended spring structure) and a polycrystalline germanium structure in the center and four connected contact pads. Here, the number of cantilevers is at least one, and the size thereof can be adjusted according to the size of the connector or the size of the subsequent connected contact pads; the shape of the contact pad is not limited to a square shape, and may be circular or polygonal. The lithography etching step includes, for example, a deep reactive ion etching step to etch the patterned polysilicon layer.

Referring to FIG. 1F, the seed layer 108 and the metal layer 110b on the back side of the substrate 100 are patterned into a hard mask layer 125 by a lithography etching step.

Referring to FIG. 1G, the substrate 100 substrate and the ruthenium oxide layer 102 are etched from the back surface of the substrate 100 with the hard mask layer 125 as an etch mask until the polysilicon layer 104a is exposed. The etching step includes, for example, a deep reactive ion etching step.

Referring to FIG. 1H, the hard mask layer 125 is removed, and then a carbon nanotube material is coated on the metal surface of the contact pad 110c of the metal layer 110a by using a patterned photoresist (not shown), and the magnetic field is applied by an external magnetic field. The carbon nanotube material is collimatedly bonded to the surface of the center contact pad 110c to form a carbon nanotube layer 130 as a probe head. After that, remove the excess photoresist material.

Figures 1A-1H depict only a single connector to facilitate the illustration of the relative positions of the layers, but may represent a general process for fabricating array connectors. The steps of forming the above layers are merely examples, but those skilled in the art can easily infer that the order of formation and the steps need to be changed in terms of component design or process. This case is not limited to the manufacturing method of this case is limited to this.

2A is a perspective view of an array connector according to an embodiment of the invention. FIG. 2B is an enlarged perspective view of the array unit of FIG. 2A. Figure 2C is a schematic cross-sectional view of Figure 2B taken along section line I-I'. Solder bumps are omitted in Figures 2A-2C for ease of description.

Referring to FIG. 2A, a connector 20 of an array of a plurality of array units is arranged, and only a single array unit is deliberately enlarged in FIG. 2B. The base substrate 200 of the base material includes an annular body structure 200a and has a columnar structure 200b at the center. The substrate 200 has a plurality of block structures 240a distributed on the annular body structure 200a, a single block structure 240b on the central columnar structure 200b and four cantilever structures 240c connected to the single block structure 240b. The single block structure 240b further has a carbon nanotube layer 230.

Referring to FIG. 2C, the annular body structure 200a and the central columnar structure 200b are a laminated structure including a polysilicon layer 204, a ruthenium oxide layer 202, and a substrate 200 (from top to bottom). As can be seen from FIG. 1G above, the substrate 100 矽 substrate and the ruthenium oxide layer 102 are etched from the back surface of the substrate 100 with the hard mask layer 125 as an etch mask until the polysilicon layer 104a is exposed, and the ring body as shown in FIG. 2B can be obtained. Structure 200a and central columnar structure 200b.

Referring to FIG. 2C, the block structure 240a distributed on the annular structure 200a, the single block structure 240b on the central column structure 200b, and the four cantilever structures 240c are also laminated, including the metal layer 210a, the seed. Layer 208a and polysilicon layer 204. The cantilever structure 240c further includes a piezoelectric material layer 206 on both sides of the junction with the block structure 240a. The size of the piezoelectric material layer 206 is much smaller than the size of the cantilever structure 240c, and its thickness and shape can also be adjusted according to design requirements.

Since the four cantilever springs are connected to the fixed end, a set of piezoelectric materials is designed, and the piezoelectric characteristics can be utilized to sense the displacement of the cantilever, and the magnitude of the forward force provided by the four cantilever springs can be estimated. Therefore, the array micro connector will have the function of displacement and force sensing.

Of course, in addition to using a piezoelectric material, a piezoresistive material or a capacitor formed by contacting the metal with the lower member by the upper member may be utilized to sense the displacement of the cantilever or to estimate the positive force by piezoresistive or capacitive characteristics. the size of.

The carbon nanotube layer 230 on the single block structure 240b is in the subsequent packaging step, and the carbon nanotubes have good mechanical properties and electrical conductivity, and can pierce the contacts of other wafers under the action of a small contact force ( The bump or BGA package solder ball contacts the oxide film on the surface, effectively reducing the contact resistance, increasing the stability of signal transmission, and achieving a good electrical connection.

The materials of the respective layers of the above structures may refer to the materials described in the foregoing processes, but the materials may still be changed depending on the component design or process.

According to another embodiment of the present invention, unlike the foregoing manufacturing flow of FIG. 1A, the step of forming the piezoelectric material layer is omitted after the polysilicon layer 104 is formed in FIG. 1A. As shown in FIG. 3, after the yttrium oxide layer 302 and the polysilicon layer 304 are sequentially formed on the substrate 300, the doping region 306 is formed directly in a specific region by doping, and the dopant substance is, for example, boron or germanium. The doped region 306 can be regarded as a piezoresistive material, and can be formed by a piezoresistive sensing mechanism formed by a subsequently formed metal layer to achieve the purpose of coplanarity detection or positive force detection. The subsequent process is referred to the manufacturing process of Figures 1B-1H above, and the final structure is shown in Figure 4.

4 is a cross-sectional view showing a connector according to another embodiment of the present invention. Solder bumps are omitted in FIG. 4 for convenience of description.

Referring to FIG. 4, the base substrate 400 of the base material includes an annular body structure 400a and has a columnar structure 400b at the center. The annular body structure 400a and the central columnar structure 400b are a laminated structure including a polycrystalline germanium layer 404, a tantalum oxide layer 402, and a substrate 400 (from top to bottom). Referring to FIG. 4, the block structure 440a on the annular body structure 400a, the single block structure 440b on the central columnar structure 400b, and the cantilever structure 440c are also laminated structures, including a metal layer 410a and a seed layer 408a. Polycrystalline germanium layer 404. The cantilever structure 440c has a doped region 406 in the polysilicon layer 404 on both sides of the junction with the bulk structure 440a. The single block structure 440b further has a carbon nanotube layer 430.

Since the cantilever spring is fixed at the fixed end with a piezoresistive material (for example, a doped region or other suitable metal), and with this piezoresistive sensing characteristic, the array micro connector will have the function of displacement and force sensing.

Therefore, the array type micro connector of the embodiment of the invention is designed with a piezoelectric material or a piezoresistive material at the fixed end of the cantilever spring connection, and can measure the displacement of the cantilever and the cantilever spring by using a piezoelectric or piezoresistive sensing mechanism, respectively. The magnitude of the positive force. The array connector of the present invention can be applied to a high-density or ultra-fine pitch joint structure, and has the mechanism of measuring the coplanarity and the positive force, thereby improving its function and industrial utilization value.

In addition, the array connector is provided with a carbon nanotube structure on the contact metal surface, and the carbon nanotube has good mechanical properties and electrical conductivity, and can pierce the bump or BGA solder ball contact surface under the action of a small contact force. The oxide film effectively reduces the contact resistance and increases the stability of signal transmission.

The manufacturing process proposed by the present invention is compatible with existing processes, and no additional steps or special materials are required, so the cost of the components is not increased. In addition, visual product design needs, adjustment process steps and / or with different shape pattern design, more flexible manufacturing of array connectors.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

20. . . Connector

100, 200, 300, 400. . . Base

100a. . . Upper surface

100b. . . lower surface

102, 202, 302, 402. . . Cerium oxide layer

104, 204, 304, 404. . . Polycrystalline layer

106, 206. . . Piezoelectric layer

306, 406. . . Doped region

108a, 108b, 208a, 408a. . . Seed layer

110a, 110b, 210a, 410a. . . Metal layer

112. . . Seed layer

120. . . Solder bump

125. . . Hard mask layer

130, 230, 430. . . Carbon nanotube layer

200a. . . Ring structure

200b. . . Columnar structure

240a, 240b, 440a, 440b. . . Block structure

240c, 440c. . . Cantilever structure

1A-1H are schematic diagrams showing the manufacturing flow of an array connector according to an embodiment of the invention.

2A is a perspective view of an array connector according to an embodiment of the invention.

FIG. 2B is a partially enlarged perspective view of FIG. 2A.

Figure 2C is a schematic cross-sectional view of Figure 2B taken along section line I-I'.

3 is a cross-sectional view showing a part of a manufacturing process of a connector according to another embodiment of the present invention.

4 is a cross-sectional view showing a connector according to another embodiment of the present invention.

20. . . Connector

Claims (12)

A connector structure suitable for use in a package structure, the connector structure comprising at least: a semiconductor substrate comprising at least one annular body structure and a columnar structure at a center of the annular body structure; at least one cantilever structure, and The columnar structure in the center of the annular structure is connected. The connector structure of claim 1, further comprising: a plurality of first block structures on the annular body structure; a plurality of solder bumps on the first block structures; a second block structure is located on the columnar structure; and a carbon nanotube layer, the second block structure on the columnar structure, wherein the cantilever structure and the annular body structure further comprise a pressure A layer of electrical material or a layer of piezoresistive material. The connector structure of claim 1, wherein the annular structure and the columnar structure are laminated structures, and further comprising a ruthenium oxide layer on an upper surface of the semiconductor substrate. The connector structure of claim 2, wherein the first and second block structures and the cantilever structure are a laminated structure, comprising a polysilicon layer, a seed layer on the polysilicon layer, and the One of the metal layers on the seed layer. The connector structure of claim 4, wherein the piezoelectric material layer is between the polysilicon layer and the seed layer. The connector structure of claim 5, wherein the material of the piezoelectric material layer comprises zinc oxide. The connector structure of claim 2, wherein the layer of piezoresistive material is a doped region located in the polysilicon layer. The connector structure of claim 4, wherein the material of the metal layer comprises aluminum, copper or gold. The connector structure of claim 4, wherein the seed layer material comprises titanium, gold or chromium. The connector structure of claim 2, wherein the material of the solder bump comprises tin, tin-silver alloy or tin-lead alloy. The connector structure of claim 1, comprising at least two opposing cantilever structures. The connector structure of claim 1, comprising at least four mutually opposite cantilever structures.